That's really a two-fer: by specifically noting the extra charge, customers get a real-world intro to the extra costs the train-wreck imposes on business. And servers get to see the effects of these costs on their own lives, both in terms of fewer hours (and lower net pay) and, presumably, lower tips (and thus lower net pay) as customers decide how much that service is worth versus the surcharge.

That's really a two-fer: by specifically noting the extra charge, customers get a real-world intro to the extra costs the train-wreck imposes on business. And servers get to see the effects of these costs on their own lives, both in terms of fewer hours (and lower net pay) and, presumably, lower tips (and thus lower net pay) as customers decide how much that service is worth versus the surcharge.